I have a really fun suggestion. It's called "Dare," and I've seen it played on several other SS FC's.

You are only allowed to post one of two things: SEVERUS or SNAPE. You post Severus if you do not wish to dare the person above you. You post Snape if you would like to issue a dare to someone.

For example:
Post 1: Severus!
Post 2: Severus!
Post 3: Severus
Post 4: SNAPE! I dare _____ (person in above post) to send user notes to 10 members you do not know and send the following message to them:
"Severus Snape is my sexy Half-Blood Prince"
So before anyone else can post, that person has to come back and post evidence of them doing the dare. For example, they couldpost links to a few of the profiles they posted UN's at. Then, when the evidence is posted, the game can continue!
Post 6: Severus!
Post 7: Severus!
Post 8: SNAPE! I dare you to ......